1. Field of the Invention
The present invention relates generally to the testing of integrated circuits (ICs). More particularly, the invention relates to the accurate testing of an IC at a pre-determined temperature, by installing temperature generation devices and temperature sensors within the IC.
2. Background
As technology advances, electronic components have become smaller and faster. Consequently, electronic components are producing hotter temperatures than before. Due to the ever-increasing amounts of heat produced in electronic systems, it is vital that electronic components, such as ICs, accurately specify the temperature range in which they can reliably operate. However, because of the complexity of modern electronic systems, determining the temperature range specification of an IC has become increasingly difficult.
Attempts to accurately determine the temperature range specification by running tests on integrated circuits in a tightly controlled temperature chamber have been largely unsuccessful. While the chamber can control the ambient temperature of the IC, the chamber cannot control the temperatures generated by the IC during its functional test or by peripheral devices surrounding the IC if it is placed in its operating environment. In modern ICs, high levels of transient currents can cause temperatures on the IC to rise within microseconds. Because of the volatile nature of modern ICs, temperature chambers are unable to precisely control the exact temperature on the chip itself. Other off-chip heat generation devices or off-chip temperature sensors have similar limitations.
Furthermore, a temperature chamber may not accurately simulate the operating environment in which many ICs will be placed. For example, when a central processing unit (CPU) is placed in its operating environment, it is surrounded by peripheral devices that generate different levels of heat, thus affecting the ambient temperature. Furthermore, it is surrounded by a computer case that also affects the ambient temperature. The performance and reliability of the CPU largely depend on the surrounding ambient temperature. The ambient temperature, in turn, depends on the heat generated by the CPU. However, none of these effects are replicated when an IC is tested in a temperature chamber. An additional disadvantage of using a temperature chamber is that a temperature chamber is large and expensive.